public class MethoDemo11 {
    public static void main(String[] args) {
        // 定一个方法，求两个数之间的和
       sum(10, 20);// 10 20 实参
        sum(100, 200);// 100 200实参
        sum(90, 200);// 90, 200 实参
    }


    public static void sum(int start, int end) {// start end 形参
        int s = 0;
        for (int i = start; i <= end; i++) {
            s += i;
        }
        System.out.println(s);
    }
}
